An effective way to ensure that LEDs produce wanted light output is to use a current driving topology, because the brightness of LEDs is directly related to their current. However, this topology may lead to the lifetime shortening of a illumination system because over-currents may flow through non-damaged LEDs in case some LEDs are damaged. This paper presents an adaptive current control circuits for LEDs, which protect LEDs in a good state by limiting the driving currents according to the number of damaged ones. The proposed control circuits consist of a simple constant-current driver and a micro-controller which monitors the voltage of LED array without any auxiliary current sensors for fault diagnosis. And the driving current is automatically controlled into 6-levels according to the number of failures.

Keywords

LED Drive;Linear Current Regulator;Over-Current Protection;Failure Detection of LED;

Kim, Eung-Seok, and Young-Tae Kim. "A Study on the Mathematical Modeling and Constant Current Adaptive Controller Design for Power LEDs." Journal of the Korean Institute of Illuminating and Electrical Installation Engineers 25.9 (2011): 8-13.